1. Field of the Invention
The present invention pertains to a pressure plate assembly for a friction clutch comprising a housing arrangement; a pressure plate held in the housing arrangement with freedom to move axially; a stored-energy element; and a wear-compensating device acting in the path of force transmission between the stored-energy element and the pressure plate and/or between the stored-energy element and the housing arrangement, where the wear-compensating device has at least one adjusting element able to move in an adjusting direction to compensate for wear and at least one spring element pretensioning the minimum of one adjusting element for movement in the adjusting direction, where at least certain areas of the minimum of one spring element extend in the circumferential direction with respect to the rotational axis.
2. Description of the Related Art
In pressure plate assemblies of this type, there is the fundamental problem that, as a result of the forces which occur during operation, comprising essentially centrifugal forces and the elastic forces produced within the minimum of one spring element, the minimum of one spring can come to rest against various other components of the pressure plate assembly, especially including the minimum of one adjusting element itself. As a result of this, additional frictional forces, which vary as a function of the operating conditions, are generated, which can oppose the movement of the adjusting device required to compensate for wear.
It is therefore the task of the present invention to provide a pressure plate assembly in which any unwanted frictional interaction between the minimum of one spring element and the wear-compensating device in particular is virtually excluded.
According to the invention, the spring element has a support arrangement to support the area of the spring extending essentially in the circumferential direction, this support being provided radially from the outside and/or radially from the inside with respect to the rotational axis.
The presence of the support arrangement prevents the minimum of one spring element from exerting pressure on the minimum of one adjusting element as a result of centrifugal forces, for example; or, depending on how the various components are installed, it prevents the minimum of one spring element from exerting pressure on the minimum of one adjusting element as a result of the elastic forces of the spring itself. When wear has occurred, therefore, this minimum of one adjusting element can then execute the required compensating movement without interference from frictional forces induced by contact with the spring element.
For example, it can be provided that the support arrangement forms a support channel for the minimum of one spring element on the pressure plate or on the housing arrangement, this channel having a boundary radially on the inside and another boundary radially on the outside.
In an embodiment which is preferred because of the ease with which it can be produced, it can be provided that the support arrangement has a support element attached to the pressure plate or to the housing arrangement, which element has a radially outer and a radially inner support wall. As an alternative, it is also possible, however, for the support arrangement to have a support recess in the pressure plate or in the housing arrangement with radially inner and radially outer boundaries. This design variant offers the advantage that the number of components to be prefabricated for a pressure plate assembly of this type can be kept small.
To make it possible for the minimum of one spring element to interact with the minimum of one adjusting element so that the adjusting element is pretensioned in the adjusting direction, it is proposed that the support channel have a channel wall separating the minimum of one spring element radially from the minimum of one adjusting element, and that the channel wall have at least certain areas which are open in the radial direction to allow the minimum of one spring element to interact with the minimum of one adjusting element.
In the pressure plate assembly according to the invention, furthermore, it is also possible for the wear-compensating device to act in the area between the stored-energy element and the pressure plate and for the support arrangement to be provided on the pressure plate. It is also possible for the minimum of one adjusting element to comprise an adjusting ring, which is able to rotate around the rotational axis to accomplish the adjustment and for the essential section of the minimum of one spring element to extend in the circumferential direction along or in the area of the adjusting ring.
The present invention also pertains to a friction clutch comprising a pressure plate according to the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.